Reel table driving apparatus for tape cassette recorder

Abstract

A reel table driving apparatus for a tape cassette recorder includes a main plate, a reel table having a reel disk rotatably installed on the main plate, a driving gear coaxially combined with the reel disk, for transmitting a driving force, and a friction gear having a larger diameter than that of the driving gear, for transmitting the driving force to the reel disk by a frictional engagement with the driving gear. The apparatus further includes a first intermediate gear selectively engaged with the friction gear, a second intermediate gear which is engaged with the driving gear, elevating means for elevating the first intermediate gear to be engaged with the friction gear in a low-speed, mode and separated from the friction gear in a high-speed mode, and an idler mechanism having a first idler gear corresponding to the first intermediate gear and a second idler gear corresponding to the second intermediate gear, coaxially installed with the first idler gear and having a larger diameter than that of the first idler gear, such that the first idler gear is engaged with the first intermediate gear in the low-speed mode and the second idler gear is engaged with the second intermediate gear in the high-speed mode.

What is claimed is: 
     
       1. A reel table driving apparatus for a tape cassette recorder, comprising: a main plate;   a reel table having a reel disk rotatably installed on said main plate, a driving gear coaxially combined with said reel disk, for transmitting a driving force, and a friction gear having a larger diameter than that of said driving gear, for transmitting the driving force to said reel disk by a frictional engagement with said driving gear;   a first intermediate gear selectively engaged with said friction gear;   a second intermediate gear engaged with said driving gear;   elevating means for elevating said first intermediate gear to be engaged with said friction gear in a low-speed mode and separated from said friction gear in a high-speed mode; and   an idler mechanism having a first idler gear corresponding to said first intermediate gear and a second idler gear corresponding to said second intermediate gear, coaxially installed with said first idler gear and having a larger diameter than that of said first idler gear, such that said first idler gear is engaged with said first intermediate gear in the low-speed mode and said second idler gear is engaged with said second intermediate gear in the high-speed mode.   
     
     
       2. The reel table driving apparatus for a tape cassette recorder as claimed in claim 1, wherein said reel table further comprises a disk pad interposed between said friction and driving gears, and a first spring installed between said reel disk and said friction gear, for elastically biasing said friction gear and said disk pad toward said driving gear. 
     
     
       3. The reel table driving apparatus for a tape cassette recorder as claimed in claim 1, wherein said elevating means comprises a slider installed on said main plate, for making a rectilinear movement in accordance with mode conversion; and a lever member, slidably connected to said slider, for elevating said first intermediate gear by moving toward or away from said first intermediate gear in accordance with the rectilinear movement of the slider. 
     
     
       4. The reel table driving apparatus for a tape cassette recorder as claimed in claim 3, wherein a slot is formed in said slider in a direction which is diagonal to a direction of the rectilinear movement of said slider, a protrusion for moving along said slot is formed on a bottom surface of said lever member, and a sloped slot, in which a rotating shaft of said first intermediate gear slides, is formed on a projecting portion of said lever member such that said first intermediate gear ascends and descends in accordance with the relative movement of said sloped slot and the rotating shaft. 
     
     
       5. The reel table driving apparatus for a tape cassette recorder as claimed in claim 4, wherein a spring for elastically biasing said first intermediate gear downward is provided on the rotating shaft of said first intermediate gear. 
     
     
       6. The reel table driving apparatus for a tape cassette recorder as claimed in claim 1, wherein said elevating means includes a slider installed on said main plate, for making a rectilinear movement in accordance with mode conversion; and a plate member slidably connected to said slider and reciprocating in accordance with the rectilinear movement of said slider, to engage said first intermediate gear with or separate said first intermediate gear from said friction gear. 
     
     
       7. The reel table driving apparatus for a tape cassette recorder as claimed in claim 6, wherein a slot is formed in said slider in a direction which is diagonal to a direction of the rectilinear movement of said slider, a protrusion for moving along said slot is formed on a bottom surface of said plate member, and said first intermediate gear is rotatably mounted on a projecting portion of said plate member such that said first intermediate gear moves perpendicularly with respect to said slider. 
     
     
       8. The reel table driving apparatus for a tape cassette recorder as claimed in claim 1, further comprising a brake member interlocked with said slider to control the rotation speed of said reel table. 
     
     
       9. A reel table driving apparatus for a tape cassette recorder, comprising: a main plate;   a reel table having a reel disk rotatably installed on said main plate, a driving gear coaxially combined with said reel disk, for transmitting a driving force, and a friction gear having a larger diameter than that of said driving gear, for transmitting the driving force to said reel disk by a frictional engagement with said driving gear;   a first intermediate gear selectively engaged with said friction gear;   a second intermediate gear engaged with said driving gear;   an elevating mechanism comprising a slider installed on said main plate, for making a rectilinear movement in accordance with mode conversion; and a lever member, slidably connected to said slider, for elevating said first intermediate gear by moving toward or away from said first intermediate gear in accordance with the rectilinear movement of the slider, thereby to elevate said first intermediate gear to be engaged with said friction gear in a low-speed mode and separated from said friction gear in a high-speed mode; and   an idler mechanism having a first idler gear corresponding to said first intermediate gear and a second idler gear corresponding to said second intermediate gear, coaxially installed with said first idler gear and having a larger diameter than that of said first idler gear, such that said first idler gear is engaged with said first intermediate gear in the low-speed mode and said second idler gear is engaged with said second intermediate gear in the high-speed mode.